proline dl-form → 1-tert-butyl 2-methyl (2S,4EZ)-4-(methoxyimino)-1,2-pyrrolidinedicarboxylate

HRID 457919

Reaction equation

HRID 457919 reaction equation
N1CCC[CH:2]1C(O)=O.[C:9]([O:13][C:14]([N:16]1[CH2:20][C:19](=[N:21][O:22][CH3:23])[CH2:18][C@H:17]1[C:24]([OH:26])=[O:25])=[O:15])([CH3:12])([CH3:11])[CH3:10].CO.C[Si](C=[N+]=[N-])(C)C>C1(C)C=CC=CC=1>[CH3:23][O:22][N:21]=[C:19]1[CH2:20][N:16]([C:14]([O:13][C:9]([CH3:12])([CH3:10])[CH3:11])=[O:15])[C@H:17]([C:24]([O:26][CH3:2])=[O:25])[CH2:18]1

Participants

6

Reactant 4

HCID 614proline dl-formHCID 887MethanolHCID 167693TrimethylsilyldiazomethaneHCID 58714586(2S,4EZ)-1(tert-butoxycarbonyl)-4-(methoxyimino)-2-pyrrolidinecarboxylic acid

Product 1

HCID 585854781-tert-butyl 2-methyl (2S,4EZ)-4-(methoxyimino)-1,2-pyrrolidinedicarboxylate

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

A solution of the oximether- and/or olefin-type 2-pyrrolidinecarboxylic acid intermediate, e.g. (2S,4EZ)-1-(tert-butoxycarbonyl)-4-(methoxyimino)-2-pyrrolidinecarboxylic acid (0.648 g, 2.5 mmol), in a 1:1 mixture of methanol and toluene (35 ml) was made. Trimethylsilyl diazomethane (3.8 ml of a 2M solution in hexanes, 7.5 mmol) was then added dropwise to the stirred solution at room temperature under nitrogen. After completion of the evolution of nitrogen gas, the resulting yellow solution was evaporated in vacuo, and the residue filtered through a pad of silica gel, eluting with ethyl acetate. Removal of solvent from the filtrate gave the methylester product, e.g. 1-tert-butyl 2-methyl(2S,4EZ)-4-(methoxyimino)-1,2-pyrrolidinedicarboxylate, as a yellow oil (0.646 g, 95% yield).

Workup

  1. customAfter completion of the evolution of nitrogen gas, the resulting yellow solution was evaporated in vacuo
  2. filtrationthe residue filtered through a pad of silica gel
  3. washeluting with ethyl acetate
  4. customRemoval of solvent from the filtrate

Sources & evidence

ORD record
ord-d1b970716bbc4b3c94fe462585b988e2
Source dataset
uspto-grants-2007_03
Patent number
US07189754B2

Linked notes

Loading…